Magneto



May 30, 1933. T, G. Louls 1,911,762

' MAGNETOV Filed Nov. 19, 195o 4'sheets-sheet 2 IN VEN TOR. 72E/vanaf 6.Lau/5 BY @a l w ATTORNEYS.

May 3o, 1933. T. G; LOUIS 1,911,762

MAGNETO Filed Nov. 19, 1930 4 Sheets-Sheet 5 @un M ATTORNEY@ May 3o,1933. T, G. Lows 1,911,762

MAGNETO Filed Nov. 19, 1930 4 Sheets-Sheet 4 INVENToR. ERM/c5 6. Lows ATTORNEYS.

Patented May 30, 1933 PATE NT OFFICE fg, TERRENCE G. IaOUIS, FSPRINGFIELD, MASSACHUSETTS, ASSIGNOR TO WIOO ELECTRIC COMPANY,OF WESTSPRINGFIELD, MASSACHUSETTS, A. CORPORATIQN- 0F MASSACHUSETTS MAGNETOApplication led November 19, 1930. Serial No. 496,750.

f 'Iphis `invention relatesr to y an improved magneto of the type havingan unwound in ductor or armature, rotatable continuously Ain onedirection, as distinguished from the type4 having a partially rotatableinducto which oscillates back and forth.

The invention makes use of certain of the important teachings of the IraE. Hendrickson Patent No.`1,736,441, 'dated November 19, 1929, but these.are utilized in a somewhat diiferent Way, resulting in a markedlydifferent magneto, having important advantages. In common with theHendrickson invention, the present invention makes use of an unwoundinductor cooperating with two cores or pole pieces of a magnetic eircuitto roduce intermittently a double break in said? circuit and at allother times to maintain said circuit closed except for the small doubleair gap between the inductor and cores, representing the runningclearance betweenf these elements. Unlike the Hendrickson'patent, thenotches in, or4 nonmagnetic portions of the inductor arediametricallyopposed and the inductor rotates between the inner ends ofthe cores,l

. the axes of which are in alignment @and also posed in planes at rightangles to the magnets and with their inner end faces nearly tangentialto the periphery of the inductor. The cores have extensions forconnection to the polar extremities of the magnetic source and the outerfaceof each such extension lies withinl a circle struck from the axis ofthe inductor as a center, and with a radius equal to the' dista-nce fromsaid axis to the outer end of a core. No parts of the magnetic circuitand no parts of the coils project outside said circle. Like theHendrickson patent, the spark is produced on the breaking of themagnetic ciruit rather than on the making thereof and, preferably also,t-he building up of flux in the magnetic circuit is allowed to occur, atleast in part, under lthe favorable condition of an lopen circuitedprimary winding. Such winding is maintained closed except at theintermittent intervals necessary to produce the spark and up of ux inthe magnetic circuit.

The problem of this invention is to produce an exceedingly small, lightweight, and compact yet highly eiiciert magneto, ca a ble of beinghoused within a very small ywheel, such for example as that of anoutboard motor, or in the small free central space available in aywheel, which also serves as a fan and in which a substantial amount ofannular space is utilized for the reception of fan blades. A iiywheel ofthe last named type is shown in the Hendrickyson patent and, as will beclear from the drawings of that patent, the Hendrickson.

magneto is incapable of being housed within the small confines of such aflywheel. What has been done in the present invention is to redesign thevarious parts of the magneto and mount them around the inductor to fitwithin the small space available. The magnets of the Hendrickson magnetohave been pulled in to lie as close as possible toy the periphery of thei'nductor, the cores and coils have been relocated to lie indiametrically opposed relation on opposite sides of the inductor andalso lmaterially shortened, but the shortening of the coils has beeneffected without materially increasing their diameter. The coreextensions have been curved to lie concentric with the axis of the rotoror otherwise so formed as not to extend beyond a circle struck with whatmay betcrmed the limiting radius, which is the radial distance from theaxis of the rotor to the outer end of a core. This radial distance hasbeen reduced to a minimum andy all other parts have been made to lieWithin the confines of a circle struck with said enable the ensuinginitiation of the building limiting radius from the axis of the inductoras a center. All this has been effected without any reduction in lengthof the magnets. rlhe same desirable long magnets of the Hendricksonmagneto can be used and yet their extremities have been made to lie at amuch smaller radial distance from the axis of the inductor.

The magneto of this invention is a unitary structure, complete initself. It can be added on to any engine without necessitating specialdesign of engine parts, as distinguished from the many prior art mag'-netos which require that the' magneto be built into the engine. Themagneto manufacturer furnishes the complete unit, even to a casing whichcooperates with the flywheel of the engine to fully enclose all workingparts, and all that the engine manufacturer has to do is to fasten thisunit in place.

The present invention represents the results of the utilization of aminimum amount of material in the most efficient and effective way toproduce a commercially successful magneto in which the parts have beencompressed and compacted into such small compass that the entire unitwill fit Within the confines of the smallest fiywheels of small engines.There are many other features contributlng to the accomplishment of thegeneral objects above set forth and these and other objects of theinvention will appear as the detailed description proceeds and beparticularly pointed out in the appended claims.

The invention will be disclosed with reference to. the accompanyingdrawings, in which Fig. l is a front elevational view of a magnetoembodying the invention;

Fig. 2 is a sectional view taken on the line 2 2 of Fig. l;

Figs. 3 and 4.- are views showing the application of the magneto to afan type flywheel,-Fig. 4 showing the flywheel and magneto casing insection and the magneto in end elevation while Fig. 3 shows the magnetoin rear elevation and its casing in section;

Figs. 5 and 6 are end and front elevational views, respectively, of oneof the st-ationary laminated field elements and coil units;

Fig. 7 is a front elevational View of the magneto frame;

Fig. 8 is a fragmentary cross sectional view illustrative of onemounting of the magneto frame on an engine;

Fig. 9 is a similar View illustrative of one form of driving means forthe magneto;

Fig. 10 is an enlarged, fragmentary, front elevational View of thebreaker point cam;

Fig. 11 is an elevational view of an outboard motor showing theapplication of the magneto thereto;

Fig. l2 is a plan view of the flywheel showing the rotor of the magnetomounted thereon; and

Figs. 13 and 14 are sectional views illustrative of the mounting of themovable and fixed elements, respectively, on the movable and xedelements of the motor.

Referring to these drawings; the magneto includes a source of magneticfiux,-such as.

the permanent magnet 20 (Figs. l and 2),- laminated extensions 21 (Fig.l), connected one to each polar extremity of the magnet and terminatingwith integrally connected but inturned cores 22 (see also Figs. 5 and6), on each of which is placed a coil element or unit, comprising aprimary and a secondary winding 23 and 2-1 (Fig. 6), respectively.Cooperating with the inner ends of the inturned cores 22 is a rotaryinductor 25 (Fig. l), which is built up of laminations in theform of ahollow cylindrical member, except for substantially diametricallyopposed notches 26, or equivalent non-magnetic portions, in its outerperiphery. The inductor, except for said portions, presents a smoothcylindrical surface running in close proximity to the concentricallycurved inner ends of the cores 22. The magnetic circuit from the magnetthrough the extensions, cores and inductor is normally closed,

except for the small double air gap between.

the inductor and cores, necessary for clearance between these elements.'Vhen, however, the two notches 26 register with the two cores, a doublebreak in the magnetic circuit is effected.

For efiiciency and to secure satisfactory results, these notches 26 needto be slightly greater in peripheral extent than the width of the corebut their peripheral extent should not be greatly in excess of suchwidth. The notches should be just long enough to afford an air gapbetween each radial wall of the notch' and the adjacent edge (upper orlower as the case may be) of the core, which air gap is of an extentsufficient to secure an effective break in the magnetic circuit. Suchgaps are measured when the radial center line of a notch coincides withthe axis of the core. Each such air gap should be of about the sameextent as, and at least no greater than, the radial gap between thecurved inner end of a core and the bottom wall of the `notch. Any excesslength in the notches detracts from the efiiciency of the machine, otherfactors being the same, and it is important to have as much peripheralextent as possible of smooth lunbroken cylindrical surface of the rotornot only in order to hold the flux in the magnetic circuit but to allowtime for flux to build up in such circuit against a short circuitedprimary circuit, as will later ap ar. y y

he primary coils are suitably connected. in a closed electrical circuit,which is controlled byr relatively lixed and movable breaker points 27and 28 (Fig. 1).l These coils may, for example, be connected as shown inseries bya wire 29. One terminal of one coil is connectedl by a wire 3()to an insulated terminal 31 and thence by a metal bracket 31', bolt 312and s ring 32 to the metallic part 33 of a breaker point lever, whichpart carries the breaker point 28. This lever is pivoted at 34 and issuitablyk mounted in and insulated from a metallic housing 35, securedto a non-magnetic plate 36 fixed, as will appear, to thestationary fieldstructure. The breaker point lever also has a part 37 of insulatingmaterial for engagement by a cam 38, carried by the rotary inductor. Thefixed breaker point 27 is supported in housing 35 andin metallicconnection therewith -and with the lfield structure of the magneto. Acondenser 39 has one terminal Connected to the insulated terminal 31 andthe other grounded to the field structure. The primary circuit is com-vpleted by grounding the other primar coil to the field structure, as bythe wire 39 The secondary coils, forming the generating Winding, may beconnected'in any suitable way. They are usually connected in series, asy a wire 40, and one of them is 'grounded as by a strap 41 secured -tothe field structure,leaving a terminal 42 for connection in any suitableway to the ignition` system of the engine,-in this case directly to aspark plug such as 43 (Figi 11) by means of a wire 44. f

From the foregoin description it will be clear that the magnetic circuitis maintained substantially closed by the inductor during the major partof its revolution. Also, that Y the primary circuit is likewisemaintained closed by the breaker points 27 and 28, which are pressedinto contact by spring 32, except when momentarily separated by cam 38.Assuming that flux has been built up in the magnetic circuit and thatthe rotor, turning in the direction of the arrow, has come into theposition shown in Fig. 1, the

notches 26 in the inductor register one with .coils and the productionof a-spark at plug 43. It will be noted that the flux change utilizedfor the production of the spark is that which occurs on the breakingrather 'magnetic 'circuit by the inductor.

than .the making of the magnetic circuit. This 1s of great importancebecause a more rapid and thus more eifectivechange of flux .is securedon the breaking than can be senotch to reach substantially to the centerof v the adjacent core at which time the breaker points will close. Theprimary circuit is thus held open long enough to reestablish theConsequently, a building up of a substantial amount of llux occurs underthe most favorable condition of an open circuited primary winding. Suchwinding then exercises no restraining influence to oppose the buildingup of iiux and a rapid increase of flux occurs in a very short time.` Ibelieve that a large part of the flux is built up at such time. Whilefull coverage-of the cores by the inductor is not secured prior to theclosing of the breaker points, there is enough coverage to permit asubstantial part of the ux to be built up and enough soV that theremainder caribe completed, even though at a slower rate, 'against theopposing influence of the closed circuited primary winding. The longdwell between the notches of the inductor is important to allowcontinued building up of flux after the breaker points close and also,of course, for the purpose of retaining the ilux already built up.

As shown, there are tivo'positions of the rotor, in each revolutionthereof, where the -magnetic circuit is broken and only one of these isutilized in the illustrated magneto. Obviously, by providing for asecond opening of the breaker points when the second break in the'magnetic circuit occurs, the second break can be utilized. In thepresent case, this second break in the magnetic circuit will undoubtedlyresult in some loss of flux although the loss is minimized by keepingthe primar)r winding-closed at the time so as to restrain a decrease ofiiux. But, after the second break, there is time to permit rebuilding offlux to compensate for the aforesaid loss. The disadvantage due vtoyloss of flux, in using two notches, is more than offset b v theadvantages resulting fronrthe double break effected by these notches.

The. foregoing description will illustrate the type. of magneto that isdesired and the preferred manner of operation thereof for securingeffective and commercially satisfactory results. The conditions statedare important and most desirable. Nevertheless the magneto can beoperated in other than the exact way described and the mode of operationas above set forth, is to be taken as illustrative of what I now believeto be the best mode of operation. Y

The present invention seeks to utilize all they desirable. Vfeatures andconditions of magneto operation` as above set forth` and yet to mountthe stationary magneto parts as closely as possible around the rotor sothat the resulting structure will be compactenough to be placed within avery small flywheel. The present invention is in sharp contrast to thatof the aforesaid patent in the sense that the magneto parts have beencompacted into small enough compass to fit within the inner annularspace of the flywheel shown in said patent, whereas the magneto of the.patent clearly will not fit into said space. And yet` the resultingmagneto is sufficiently effective to satisfy the exactingr demands ot'the trade.

What has been done is to pull in the magnet 20, locating it so that atitsneutral point. it lies closely adjacent and nearly tangential to theperiphery of the rotor (Figs. 1 and The magnet is no shorter than thatof said patent. rlhe inductor itself is made as small as possible butlittle reduction can be effected here because ofthe fixed factor of alarge central opening for the engine crankshaft. Also, there is adefinite minimum cross sectional area of iron required for conductingthe desired amount of linx. 'The minimum cross sectional area is at thenotches and, as shown, is half that at unnotched portions of theinduct-or. Since the flux, in flowing from one. core to another,

` dividesinto two streams yon opposite sides of the rotor axis, thesetwo portions of least area do not' restrict the fiow for each takes onlyhalf the flux. With the outside diameter of the rotor fixed to a minimumcompatible with the conditions imposed, cores, of a length as short aspossible, compatible with coil requirements, are mounted one on eachside of the rotor. These cores extend radially from the inductor andpreferably in diametrically opposed relation, or substantially so. Thecoils are made as short as possible. As shown, the coil element as awhole, is of a diameter twice its length. The diameter of the coil ismade as large as possible so that its length may be made as short aspossible. These, the preferred proportions of the coil element, are mostdesirable and important as enabling the compact arrangement. The coilelements are made to substantially fill the space between the cores andthe magnet or, more properly, the surface 46 of the polar extension 21.By this arrangement the length of the core, measured from its curvedinner face tn its junction with ,the inner face 47 of its polarextension 21 is substantially less than the radius of the inductor. Theextension 21, at its lower end, must have a definite minimum crosssectional area for fiux conducting purposes and this means an additionto the outer end of the core. The aforesaid conditions fix the minimumradial limits of the magneto. The radial distance from the axis of theinductor measured along `an axis of the core to the outer curved face 48of an extension 21 has been reduced to a. minimum for the desiredmagnetic and electrical characteristics of the machine. Such distance iswhat I term the limiting radius. iVith this radius as a limitingdimension, I have made all other parts of the magneto proper, such asthe magnets and polar extensions, lie within the limits of a circlestruck with said radius from the axis of the inductor as a center. Asshown, the surfaces L18 are curved concentrically with thel axis of theinductor but they may1 be otherwise formed and still lie within thelimits specified. 'l`lul magnets, although of thel simple, straight-barform desirable for manufacturingl economy, are of the usual length andyet by moving them in as closely as feasible to the periphery of theinductor, their ends lie wholly within said circle.

Referring now to the 'details of the magneto, the permanent magnet- 20is a composite one. composed of a central stack of superposed straightbar magnets of rectangular cross section (Fig. 2) and of equaldimensions and other like magnets placed on edge, one on each side ofthe central stack. The width of the outer magnets, thus placed on edge,is substantially equal to the combined thicknesses of the magnets whichcorn-l pose the central stack. This assembly of magnets is suitably held(as by endwise pressure) between the upper ends of the two laminatediron extensions 21 each of which is preferably recessed as shown, toreceive and closely fit the assembly of magnets. The laminatedextensions 21 are suitably bound together as by rivets 49 and by bolts50 and 51,-these bolts serving also to bind the entire stationary fieldstructure to a supporting frame, herein shown as a flat non-magneticmetal plate 52, suitably recessed to enable the engine crankshaft s tolThese additional laminations are, for the most part, placed between thecore laminations and plate 52 in order to fill up the clearance space.The core laminations have integral parts forming the extensions. Thelaminations 21 are cut to the shape of the extensions except that theyterminate with rounded lower ends through which the bolt 51 passes. Afewl lamina-tions, similar to those marked 21', are placedin front ofthe core laminations to form a shoulder for the coil element.

Each coil element comprises a hollow cylindrical casing 53 'ofinsulating material closed at one end and having inner and outercircular walls projecting from the end wall in concentrical relation;forming an annular space into which the secondary coil 24 is placed.Usually sealing compound 54 (Fig. 6) is poured into this space to sealthe coil in its casing and a split sealing ring 54 is applied to closethe outer end of, the

annular part of\said casing.V The primary coil is pressed into the spaceWithin the inner circular wall. The casing 53, with the coils assembledtherein, is slid onto a core 65 nations 21 and 21,'1--also of the 22until its closed end abuts-the shoulders formed by the laminations 21and 21. The flat face 47 of these laminations affords a substantial areafor'such engagement by the casing 53.

vIt is important to hold these casings 53 in place .on their cores, notonly to prevent breakage of the electrical connections but also toprevent axial displacement of the coils on the cores such as might causethe coils to rub on the revolving rotor 25 and' be damaged thereby. Tothis end, I may provide on each core a flat strip 55 (Fig. 6) of metal,secured thereto by one of the rivets 49. After the casing 53 has beenput in place, the end of this strip is bent over the inner and open endface of the casing (Fig.

v5) to hold it in place on ,',the'core with its closed end pressedtightly against the surface 47. yAs an alternative or as additionalsecurity, I provide for the purpose, outwardly turned ears'55 ona plate56, secured by cap screws 5 6 to plate 52 (Figs. 1 and 7'). These earsare so located that each will engage an inner face of a casing 53 andforce it against its locating shoulders. T hese securing means not onlyprevent axial displacement of the coils but also, by frictlonalengagement therewith tend to prevent the coils from turning on thecores. Additional security against turningV of the coils may be Vhad byWedges 57 (Figs. 5 and V6) placed between the cores and the primarycoils 23. It will be seen that the stationary elements ofthe magneto areAbound together into one unit andvheld tothe support 52 by the bolts 50and 51. The heads ofthese bolts are preferably countersunk (F1g.'.2)into the support 52 so' as to lie flush with [its back face'and thebolts extend throughthe support, spacing washers 58, and the lambleslimited pivotal movement -of the coxi` nected elements 21, 21 and 22about the bolt 50 as an axis. For example, the hole through which bolt51 passes, may be made larger than the bolt to permit this action, asshown in Fig. 6.V In this way, the inner ends of cores 22 may be movedtoward or away from the periphery of the inductor .to adjust theclearance therebetween.

rlhe rotary inductor may be mounted various ways. The ysimplest way isto fix it directly to the crankshaft or flywheel (Fig.I 12). VIf thisplan be followed, there will be nodmagneto partsrequiring lubrica'vtion. The disadvantage of this plan is that the magneto rotor willpartake of any un'- evenness in the running of the crankshaft orflywheel, such as wobbling or eccentricit For maximum elliciencyfa closerunning tbetween the rotor and cores is needed and it is diilicult tomaintain this close fit unless the crankshaft runs true, which it oftendoes not. A preferred plan which guards against port a bearing sleeve 61fixed to the rotorl 25. This stud projects forwardly from the Vfrontfacevof plate 52 and encompasses the'A crankshaft a with suilicientclearance there# between to take care of any unevenness in the runningof the crankshaft. may then be driven in any suitable way from thecrankshaft or flywheel so as to' prevent.

the wobbling or eccentric movements of the latter from beingcommunicated to the rotor. For example, Va drive pin 63 (Figs. 4'

and 9) supported eccentricall fromrthe flywheel f may project forwar ytoward the -rotor with'its free end received in` an open-.j

ing therein. This drive pin is dlesirablyv somewhat ilexible (thatshown'is of .musicj wire) and it may also .be flexibly supported as bythe split collar 64 in which it is sup-V ported for limited rockingmovement. A spring 65 von the drive pin may be used a vmeans forretaining the inductor 25 in proper axial position on its bearing studAs shown herein, the stud has a flange. 66 at one end which is securedwith plate 56 by cap screws 56' to plate 52.

The rotor wheel, it is desirable to do so in the manner shown in Figs.12 and 18. The inductor is pressed onto a sleeve 67 which encompassesthe hub L of the flywheel f and has a freely sliding t therewith. Thissleeve has a flange 68 which is secured by screws 69 to the flywheel.The inductor, after having been pressed onto the sleeve with a drivefit. is afterwards machined so that its periphery is true and concentricwith the sleeve. If the inductor were pressed onto the hub h by theengine manufacturer and not thereafter machined, there is a danger thatits periphery might not be true because of possible distortionsresulting from the driving of it onto the hub. The suggested planenables the magneto manufacturer to furnish to the engine manufacturer aproperly machined inductor with a convenient attaching means thereforand one which can be applied with assurance that the periphery of theinductor will not be distorted by the engine manufacturer in the act offastening the inductor in place.

The stationary magneto elements, carried by plate 52 may be mounted onthe engine in any suitable way. In many cases, these elements need to bemovable within the limits, about the axis of the inductor, to vary thetiming of the spark. In other cases, they may be rigidly fixed. In mostcases' also, it is desirable that the magneto be en' closed to protectthe parts and I rovide V a casing 71 of thin pressed metal or thispurpose. This casing is substantially cup shaped in form, having an endwall 72, perforated centrally to encompass the crank-` shaft s and acircular flange 73. The latter cooperates with some circular part of thel flywheel, as shown in Fig. 4, to afford an enclosure for the magnetoparts. lVhere enclosure of the parts is not desired, the casing may beomitted. When the casing is used, the inner face of its end wall 72 liesflat against the back wall of plate 52 (Fig. 4) and these two elementsare secured to an suitable part of the engine, such as the hu z. of thecrankcase, by -cap screws 74 (Fig. 8). This hub preferably has amachined cylindrical surface 75 to closely fit in the central hole 76(Fig. 3) of plate 52 as a pilot,thereby locating the stationary magnetoelements in proper relation with the axis of the crankshaft. Thislocating 5 feature is obviously not so important where the magneto isprovided with a bearing of its own for the rotary inductor.

Where it is desirable to shift the relatively stationary elements of themagneto 9 about the axis of the inductor for timing purposes, I providethe mounting shown enerally in 11 and in detail in Fig. 14. n Fig. 11,there is shown a two cylinder outboard motor of a well known ty ,--the 5cylinders being marked '0, the cran case o',

the gasoline tank t and the flywheel f. The crankshaft s passes out ofcrankcase c through a hub g. The inductor is mounted on the inner faceof flywheel f as above described, and as shown in Figs. 12 and 13. Therelatively stationary elements of the magneto are the saine as shown inFig. 1 and the7 are contained within the casing 71 and bolted to theframe plate 52. The pilot hole 76 of plate 52 is received on theperiphery of a split sleeve 77, having at one end a circular flange 78.The plate 52, end wall 72 of casing 71, and a plate 79 interposedbetween wall 72 and flange 78, are clamped to said flange by bolts 80.The sleeve 77 is turnably mounted on a cylindrical part 81 of hub c/ andits end flange 78 seats against a shoulder 82 on this hub. A splitclamping strap 83 encompasses the other end of the split sleeve 77 andserves to hold the latter frictionally to the hub,a bolt 84 serving todraw together the split ends of the strap. The member 79 extendsradially beyond casing 73 (Fig. 11), ter minating with a handle 85, bywhich the sleeve 77 and with it the magneto parts carried by frame 52,may be shifted about the axis of` shaft s to effect variations intiming.

The breaker point operating cam 38 may be fixed to the inductor asindicated in Fig. 12 or it may be movably mounted thereon as shown inFig. l. In Fig. 1 the cam 38 is integrally connected to an annular ring86, which encompasses the bearing sleeve 61 of the inductor and liesflat against the outer end face thereof. Ring 86 is pivoted to theinductor at 87 and carries a weight `88. A spring 89, interposed betweensleeve 61 and a spring seat 90 acts to press the cam 38 radiallyoutwardly. Such movement is limited by the abutment ofthe lower part ofring 86 with the lower part of the sleeve.

The weight 88, after the inductor exceeds av certain predeterminedspeed, tends to move radially outwardly by centrifugal force and therebydraw cam 38 inwardly against the action of spring 89 sufficiently toprevent it from moving the breaker point lever,-- thus governing theengine by cutting out the ignition. The tension o f spring 89 ispreferably adjustable. Its seat 90 (Fig. 10) is threaded on a stud 91fixed to cam 38. A flat spring 92 secured at one end to ring 86 bearsagainst the serrated upper end 93 of seat 90 to hold it in its variouspositions of adjustment.

In Figs. 1 and 2, I have indicated how the rotary part of the magnetomay. be lubricated. A wick 94, leading from the engine crankcase or anysuitable oil reservoir extends through the bottom of `casing 71 into thesame, passing between 'pla-te 56 and flange 66 and through stud 60. Anaxially directed slot is eut in stud 60 and the wick is bent toglie inthis Slot and engage the inductor sleeve 61.

The operation of the magneto should be clear from the foregoingdescription andl need only be briefly summarized. The inductor 25,driven as indicated or in any other suitable way from theengine,'rotates continuously in the direction of the arrow shown inFig. 1. This inductor, for the larger part of each' revolution,cooperates with the cores 22 to maintain a substantially closed magneticcircuit from the magnetic source 20 through the primary and secondarycoils on coresl 22. Periodically, this normally closed magnetic circuitis suddenly broken at two points by the two notches 26 in the inductorcoming simultaneously into register with the two cores. At or -aboutVthis time, the breaker points 27 and 28 are separated by cam 38 and theprimary. circuit is thereby broken. This results in a sudden decrease offlux in cores 22 and the generation of an E. M. F. in the secondarywindings. After this E. M. F. has been produced, the primary circuit ismaintained open for a short interval until the unnotched part of theinductor again comes into very close proximity to the cores, permittingthe rapid building up .of flux in the magnetic circuit under the mostfavorable conditions.

The advantages of the invention can be best appreciated and visualizedfrom an in spection offFigs. 3 and 4 and a comparison of them with thedrawings of the above mentioned patent. The flywheel f isV of the sainetype and of the same size. A large part of4 its area is utilized for thereception of fan blades b, leaving only a very small inner cylindricalspace available for the magneto. The Hendrickson magneto is altogethertoo large to fit into the aforesaid small available space. The magnetoof this invention, however, has been made to fit into such. space andthis' has been done without shortening the desirable long magnets of theHendrickson magneto and without sacrifice 1n c ffectiveness of themagneto. The magneto 1s highly eicient .and adequately meets the demandsof the trade, yet its parts have been compacted into much smallercompass than has been possible` heretofore, so far as I am aware.Another graphic illustration of the compact arrangement of-magneto partsis found in Fig. 11, which shows the same magneto housed within the verysmall iiywheel of a portable outboard motor, such as are widely used onrowboats andthe like. Actually,the magneto will fit within a circularspace somewhat less than seven This striking result inches in diameter.

. has beeneifected by a most eilicient utilizaperiphery of the inductorinto a new and exceedingly effective arrangement. The advantagesstressed in the Hendrickson patent are realized in this magneto and thesmall, compact and relatively light weight magneto has been obtainedwit-hout a ,corresponding reduction in etliciency.

The invention hasA been disclosed herein, in an embodimentat presentpreferred, with detailed variations, for illustrative purposes but Idesire to claim my invention in the broadest possible legal manner.

.What I claim is: v

1. A magneto, comprising, an unwound rotary inductor in the form of acylindrical member of magnetic material except for substantiallydiametrically opposed noninagnetic portions in its outer periphery, apair of cores of magnetic material mounted in vsubstantiallydiar'netrically oppbsed Arelation one on each side of the inductor withthe inner end of Veach disposed in closely adjacent relation to saidperiphery, a permanent magnet substantially paralleling the cores anddisposed nearly tangential at itsneutral point toV said periphery,members of magnetic material one for each coreforconnecting the outerend of each core to the adjacent polar extremity of said magnet, saidmagnet and members lying entirely within a circle struck from the axisofsaid inductor as a center and with a radius equalto the radial distancemeasured along the axis of a core from the axis of the .inductor to theouter face of the member connected to such core, and coils on saidcores, said cores constituting the sole meanskfor conducting the lluxfrom said magnet to theinductor.

2. A magneto, comprising, an unwound rotary inductor in the form of acylindrical member of magnetic material except for substantiallydiametrically opposed non-magnetic portions in its outer periphery, apair of each core to the adjacent polar extremity of said magnet, saidmagnet and members lying entirely within a circle struck from the axisof said inductor asa center and with a radius equal to the radialdistance measured along the axis of a core from the axis of the'inductorto the outer face of the member connected to such core, and coils onsaid cores, said core's constituting the sole means for conducting4'theflux from said magnet to the inductor.

3. A magneto, comprising, an unwound rotary inductor in the form of acylindrical member of magnetic material except for sublstantiallydiametrically opposed non-magnetic portions in its outer periphery, apair of cores ot' magnetic material mounted in substantiallydian'ietrically opposed relation one on each side ot the inductor withthe inner end ot each disposed in closely adjacent relation to saidperiphery, each ot said non-magnetic portions having a peripheral extentnot greatly in excess of the width of a core, a permanent magnetsubstantially paralleling the cores and disposed nearly tangential atits neutral point to said periphery, members ot magnetic material onefor each coro for connecting the outer end ot' each core to the adjacentpolar extremity otl said magneti, said magnet and members lyinglentirely within a circle struck from the axis ol said inductor as acenter and with a radius equal to the radial distance measured along theaxis of a core from the axis of the inductor to the outer face of themember connected to such core, said cores constituting the sole meansfor conducting the flux from said magnet to the inductor, primary andsecondary windings on said cores, a closed electrical circuit includingsaid primary winding and breaker point mechanism for opening and closingsaid circuit and maintaining said circuit normally closed and openingsaid circuit when said non-magnetic portions break the magnetic circuitthrough said cores.

4. A magnet-o, comprising, an unwound rotary inductor in the t'orm ot acylindrical member of magnetic material except for substantiallydiametrically opposed nonmagnetic portions in its outer periphery, apair ot cores of magneticr material mounted in substantiallydiametrically opposed relation one on each side ot the inductor with theinner end of each disposed in closely adi-ores and disposed nearlytangential at its neutral point to said periphery, members otl magneticmaterial one for each core for connecting the outer end ot' each core tothe adjacent polar extremity of said magnet, and coils on said cores ofa diameter 'greater' than their length and substantially filling thespace between their cores and the adjacent parts of said magnet.

5. A magneto, comprising, an unwound rotary inductor, relativelystationary field elements comprising, a magnet, a pair ot cores andextensions one from each core 'for connecting them one to each polarextremity ot the magnet, said cores disposed on opposite sides of theinductor with their inner ends in close proximity thereto and extendingradially away from the inductor with jacent relation to said periphery,a perma-` nent magnet substantiallyT paralleling the their outer endsconnected one to each extension at one end thereof, said magnetextending in closely adjacent relation and nearly tangential at itsneutral point to the periphery of the inductor, the outer faces of saidextensions substantially converging in a direction i'rom the core endsand toward the magnet ends, said cores constituting the only fluxconducting means cooperating with the inductor, and generating windingson said cores.

(i. A magneto, comprising, an unwound rotary inductor, relativelystationary field elements comprising, a magnet, a pair of cores andextensions one from each core for connecting them one to each polarextremity ot the magnet, said cores disposed on opposite sides ot' theinductor with their inner ends in close proximity thereto and extendingradially away from the inductor with their outer ends connected one toeach ex` tension at one end thereof, said magnet extending in closelyadjacent relation and nearly tangential at its neutral point to theperiphery of the inductor, said cores consti tuting the only fluxconducting means cooperating with the inductor, and generating windingson said cores, all the aforesaid elements lying within a circle struckfrom the axis of the inductor as a center and with a radius equal to theradial distance meas' ured along the axis ot' a core from the axis ofthe, inductor to the outer face of such cores extension.

7. A flywheel magneto, comprising, a relatively stationary but angularlyadjustable and substantially cylindrical casing closed at one end andthe opposite end of which is adapted to be substantially closed by theflywheel, a rotary inductor disposed centrally within said casing andmounted substantially in axial alignmentwith the flywheel to turntherewith; and field elements mounted stationarily in the casing andcomprising a magnet, a pair of cores, and extensions one for each corefor connecting them one to each polar extremity of the magnet, saidcores mounted on opposite sides of the inductor with their inner ends inclose proximity thereto and extending radially away from the inductorwith their outer ends con nected one to each extension at one endthereof, said extensions extending along the inner wall of said casingin the same general direction to said magnet, said magnet extending inclosely adjacent relation and nearly tangential at its neutral point tothe periphery ot the inductor, said cores constituting the only fluxconducting means cooperating with the inductor; and generating .windingson said cores.

8. A magneto, comprising, a pair of cores mounted in axial alignmentwith their inner ends in axially spaced relation, an unwound inductorrotatable between said inner ends and in closely adjacent relationtherewith, said inductor having in its periphery diametrically op osednon-magnetic portions,

each of a peripheral extent not greatly in excessl of the width of acore, the inductor except for such portions being cylindrical, apermanent magnet extending parallel to the cores and closely adjacentand nearl tan* gentlal at its neutral point to the periphery of theinductor, an extension on each core for connecting it to the adjacentpolar extremity of said magnet, primary and secondary coils on eachcore, a closed electrical circuit -including the primary coils, andbreaker point mechanism for normally maintaining said circuit closed andfor opening it when said non-magnetic portions align with the cores andproduce a double break in the magnetic circuit from said magnet, all theaforesaid elements lying within a circle, the center of which is theaxis of the inductor and the radius ofwhich is the distance measuredalong the axis of a, core from the axis of the inductor to the outerface of the extension connected to said core.'

9. A flywheel magneto, comprising, a relatively stationary circular andsubstantially cup s aped casingto cooperate with a fly-A wheel andprovide a substantially cylindrical enclosure, an unwound inductordisposed centrally within said casing and mounted in axial alignmentwith the flywheel to rotate therewith, said inductor being a cylindricalmember of magnetic material except for substantially, diametricallyopposed non-magnetic portions in its periphery, a pair of cores mountedinvsubstantialy diametrically opposed relation with the innerends ofeach in closely adjacent relation to the periphery of the vinductor andextending in opposite directions from the inductor to the inner wall ofsaid casing, an extension from the outer end of each core extendingalong said wall, a permanent magnet substantially paralleling the coresand Ainterconnecting lsaid extensions and lying closely adjacent andnearly tangential at its neutral'point to the periphery of the inductor,primary and secondary windings on said cores, a closed electricalcircuit including the primaryfwinding,vand breaker point mechanism forcontrollin said circuit.

10. magneto, comprising, a rotary inductor, a pair of cores mounted oneon each side of the inductor in substantially diametrically opposedrelation with their inner ends in close proximity to the periphery ofthe inductor, each core being of a length no greater than the radius'ofthe inductor, a coil element on each core of a diameter substantiallytwice its Vaxial length, an extension from the outer end of each core,the inner face of each extension extending from its core in parallelrelation with the outer end face of the coil element on such core toVsupport, a cup-like casing havin the periphery of the element and thenturning and extending in adirection parallel to the axis' of saidelement and in closely adjacent relation to the periphery thereof andterminating with ,a magnet receiving end, and a permanent magnetextending substantially parallel with the axes of the cores andinterconnecting said ends of the core extensions and disposed closelyadjacent and nearly tangential at its neutral point to the periphery ofthe inductor, said magnet and extensions lying entirely within a circlestruck from the axis of the inductor as a center and with a radius equalto the distance taken along the axis of'a core from the axis of theinductor to the outer face of the extension.

11. A magneto, comprising, a rotary inductor, a pair of cores mountedone on each side of the inductor in substantially diametrically opposedrelation with their inner exids in close proximity to the periphery ofthe inductor, each core being of a length no greater than the radius ofthe inductor, a coil element on each core of adiameter substantiallytwice its axial length, an extension from the outer end of each core,the inner face of each extension extending from its core in parallelrelation with the outer end face of the coil element on such core to theperiphery ofthe element and then turning in a direction parallel to theaxis of said elef ment and in closely adjacent relation Ito theperiphery thereof and terminating with a magnet receiving end, and apermanent magnet extending substantially parallel with the axes of theco-res and interconnecting said ends of the core extensions and disposedclosely adjacent and nearly tangential at its neutral point to theperiphery of the. inductor, said inductor, cores and extenslons forminga magnetic lcircuit, from said magnet of which the inductor is themovable y element and said cores constituting the only part of saidcircuit which cooperates w1t the inductor, said magnet and extensions1ying entirely within a circle struck from the axls of the'inductor as acenter and with a radius equal to the distance measured along the axisof a core from the axis of the 1nductor to the outer face of theextension.

12.. A flywheel magneto, comprising, a an end walll secured to said suport an an outwardly projecting perip eral llange, an annular bearingfixed to and projecting from said support within said Bange, a rotaryinductor rotatably mounted on said bearmg and comprising a laminatedmember of hollowl cylindrical form except for substantiallydiametrically opposed non-magnetic portions in its perlphery, means forrotatmg the inductor, stationary 1 field elements mounted on saidsupport and including a of for connecting each to a polar extremity ofthe magnet, said cores mounted on opposite sides of the inductor andextending radially therefrom toward the ripheral vvall of said casing,said extensions extending along said wall from the cores to the ends ofthe magnet, primary and secondary windings on said cores, a closedelectrical circuit including the primary Winding, and breaker pointmechanism for controllin g said circuit.

13. A ywheel magneto, comprising, a stationary support having a hollowcylindrical stud extending from one face thereof, a drive shaft passingthrough said stud, a driving member fixed to said shaft, relativelystationary and movable magneto elements effective on relative rotationto generate an electromotive force, the movable element being mountedto-turn on said stud with one end face adjacent said support and theother adjacent an end face of said member, and a drive pin fixed to saidface of said member eccentrically thereof and extending substantiallyparallel to the axis thereof to said movable element with its free endoperatively engaged with the latter for turning the same.

14;. A flywheel magneto, comprising, a support, a drive shaft, a memberfixed to said shaft, a substantially cup-shaped casing having a flat endWall and a circular flange thereon cooperating with said member toprovide an enclosure, a relatively thin flat plate contiguous with theinner face of said end Wall and secured With the latter to said support,both plate and Casing having a hole through which said shaft passes, amagnet and polar extensions each connected at one end to one polarextremity of the magnet,y

both magnet and extensions being supported by said plate Within saidenclosure, a pair of cores connected one to each extension at the otherend thereof and extending radially toward the center of the casing,coils on said cores, and an unwound inductor fixed to the inner face ofsaid member and rotatable between the inner ends of said cores.

In'testimony whereof I have aihxed my signature.

TERRENCE G. LOUIS.

